1. Field of the Invention
The present invention relates to an input/output structure of a dielectric waveguide, and, in particular, to an input/output structure suitable for mounting on a printed circuit board, and the like.
2. Description of the Related Art
There has been used a dielectric waveguide input/output structure comprising an input/output electrode formed on a bottom surface and lateral walls of a dielectric waveguide resonator which performs input and output, as an input/output structure for directly mounting, on a printed circuit board, a dielectric waveguide filter, a dielectric waveguide duplexer, or the like comprising a plurality of dielectric waveguide resonators coupled to each other.
FIG. 8 is a lower perspective view illustrating an example of a dielectric waveguide filter comprising a conventional dielectric waveguide input/output structure described in JP 2002-135003A. A dielectric waveguide filter 100 comprises dielectric waveguide resonators 102, 102 having a rectangular parallelepiped shape as an outer shape and TE mode as a resonant mode. The dielectric waveguide resonators 102, 102 are coupled to each other via a slit 103. In a bottom surface 102b of each of the dielectric waveguide resonators 102, 102, there is provided a band-like input/output electrode 105 that extends from the center on one side of the bottom surface 102b to a direction of opposing sides. Each dielectric waveguide resonator 102 is covered with an electrically conductive film, except for opposite sides 106, 106 of the input/output electrode 105 and for a lateral opening 107 surrounding the input/output electrode 105 in a lateral surface 102a with which the input/output electrode 105 is in contact.